GGT circulates in the blood in at least four different molecular forms, which are categorized according to their molecular weights as large GGT (b‐GGT), medium GGT (m‐GGT), small GGT (s‐GGT), and free GGT (f‐GGT); their concentrations and ratios vary under different pathological conditions, and different patterns of plasma GGT fractions have been described in certain liver diseases. Here, GGT1 is linked to liver disorder.